Police have appealed for calm after officers were attacked with petrol bombs during a dissident republican march in Derry.
A number of missiles were hurled by young people at a PSNI Land Rover which was monitoring the parade in the Creggan area of the city on Sunday afternoon.
The police said there were no injuries.
A PSNI spokesperson said: "Our officers have come under attack in Creggan with petrol bombs and other objects thrown at their vehicle while in attendance at an un-notified Easter parade.
The parade, which travelled to the City Cemetery, was led by a number of people in paramilitary-style dress.
Assistant Chief Constable Bobby Singleton said the force had received "strong" intelligence that dissidents were planning to launch terror attacks against officers on the bank holiday.
Police had increased security measures in response to the un-notified parade.
The New IRA was responsible for the attempted murder of Detective Chief Inspector John Caldwell in Omagh, Co Tyrone, in February.
He remains in hospital after being shot several times by two gunmen.
Last night, the local police commander warned that as the parade has not been notified to the Northern Ireland Parades Commission, anyone taking part would be committing a criminal offence.
Journalist Lyra McKee was shot dead while observing rioting in the Creggan area in April 2019 when a New IRA gunman fired several shots towards police officers.
The PSNI said the majority of Easter parades across Northern Ireland passed off without incident.
But police are investigating after a masked colour party led a parade by the Irish Republican Socialist Party along the Falls Road in west Belfast.
A statement from the PSNI said footage of the event will be reviewed as part of an investigation into potential offences under the Terrorism Act.
Police leave was restricted and shift patterns changed to ensure the maximum number of officers were available for frontline duties over the Easter weekend and the coming week, which includes the visit of US President Joe Biden and British Prime Minister Rishi Sunak to Belfast.
Around 300 officers from police forces in Britain have also been brought in to provide additional specialist support.
'Out of step' with the community
Sinn Fein vice president Michelle O'Neill described violent scenes as "deplorable".
She said: "25 years on from the Good Friday Agreement this needless street disorder in Derry has no place in our society.
"As political leaders we must stand united appealing to all those concerned to end these attacks and refrain from further threats of violence, whether in Derry or North Down.
"This type of illegal and anti-community activity is deplorable and out of step from wider community and public opinion.
"Our focus is on the future and on the future of our young."
SDLP leader and Foyle MP Colum Eastwood said the people of Derry "totally reject" the staging of the march.
"This is an illegal march, marching through an area where people don’t want them," Mr Eastwood told RTÉ's News at One.
"The people of Derry have roundly rejected dissident republicanism, that old ideology that just filled our jails and graveyards. These people are still intent on carrying that on.
"I think it’s important that people understand that this is a tiny minority of our community," he said.
"The people of Derry totally reject them and have chosen a very different path.
"It is a very difficult balancing act for the police. It’s an illegal parade and it goes against the wishes of the people of the city.
"Having spoken to the police, the police will not want to be going in too close to it.
"I think they’ll probably police it from a distance and see what happens after that, Mr Eastwood added.
"If there is trouble, the only trouble they (march organisers) are bringing is to the people of Derry, which is a bizarre way to go about your business if you say that you care about this community and this country.
"Wrecking your own community is a very strange approach to politics," he said.
Additional reporting Vincent Kearney
